Large quantities of paraffins are consumed in commercial processes which produce motor fuel by alkylation reactions or produce ethers including methyl tertiary butyl ether (MTBE) by etherification reactions. The production of these compounds is often a multistep process which requires recycling various intermediate paraffin-rich process streams. For instance a large etherification complex which consumes isobutylene will normally contain a catalytic paraffin dehydrogenation unit and a catalytic isomerization unit in addition to the etherification unit. These additional units convert normal butanes into the isobutylene consumed in the etherification unit. The recycled process streams often contain nonparaffinic compounds detrimental to the catalysts and adsorbents employed in these processing units, and it is necessary to remove the nonparaffinic compounds by some means.
The fresh feed stream to a hydrocarbon conversion unit or to an overall processing complex may also contain contaminant compounds which are injurious to the catalyst used in the process. In the case of a paraffinic fresh feed stream produced in a petroleum refinery these are likely to be indigenous sulfur compounds such as mercaptans, oxygenates (e.g., methanol), water and olefins. Natural gas-derived butane feed streams may also need treatment to remove mercaptans and other contaminants.